[T]he representation of clouds in climate models (and of the water vapour which is intimately involved with cloud formation) is such as to amplify the forecast warming from increasing atmospheric CO2—on average over most of the models—by a factor of about three. In other words, two-thirds of the forecast rise in temperature derives from this particular model characteristic. Despite what the models are telling us—and perhaps because it is models that are telling us—no scientist close to the problem and in his right mind, when asked the specific question, would say that he is 95 per cent sure that the effect of clouds is to amplify rather than to reduce the warming effect of increasing CO2. If he is not sure that clouds amplify global warming, he cannot be sure that most of the global warming is a result of increasing CO2. Uncertainty, scepticism and the climate issue, Garth W Paltridge, in 'Climate Change: the Facts,' edited by Alan Moran, 2015The 'forecast rise in temperature' referred to by Professor Paltridge is that made by the Intergovernmental Panel on Climate Change (IPCC). The book in which Prof Paltridge's essay appears is a collection of skeptical essays, and one which, like the website Watts up with that? is at first persuasive to non-scientists like myself. But then so too are most of the arguments on the other side of the debate; the ones agreeing with what has become the mainstream view, that anthropogenic climate change is happening. (There's also an equally convincing website: RealClimate.org.)
We know that science is not a consensual process. So what are policy people to make of these irreconcilable differences? We can all agree that there are uncertainties, not only about the fact of climate change but also about the details: the magnitudes, the causes, the impacts. We can also agree that these uncertainties are not going to disappear any time soon. Conventional policy has a hard time trying to deal with such uncertainty. It seeks to identify, with a high degree of certainty, those causes, magnitudes and impacts of climate change, then come up with something to tackle the root causes. Conventional policy has identified greenhouse gases as those causes and keeps coming up with measures aimed at cutting emissions of those gases into the atmosphere. Or, more cynically, aimed at pretending that such cuts in emissions will happen: these measures are unpopular, divisive and expensive. As well, the costs are all upfront and the climate benefits - there's almost universal agreement about this too - will be slow in coming and probably not very significant. (It's likely any cuts will have beneficial effects on things other than climate, but they are not driving policy.)
Conventional policy, then, is failing. I think there's a broad consensus about that too. Some think it's too little; others think it's too drastic. But either way, it's not good enough. Even in their own terms, Kyoto and subsquent agreements are failing.
So here's my suggestion. Instead of targeting what might or might not be the cause of what might or might not be anthropogenic climate change, why not target exactly what we want to achieve? It could be an array of ranges within which physical, biological, social and financial indicators must fall, for a sustained period. We could aim for relative and sustained stability in those indicators that are important to plant, animal and human life. A Climate Stability Bond regime would do this, regardless of what we currently think is driving the climate. It is not only clouds (see excerpt above) whose contribution is uncertain: it's the relative contribution of the various greenhouse gases or any of a large number of other variables, anthropogenic or not. The conventional approach, which looks for root causes before doing anything significant, isn't working, and cannot work when our knowledge of such causes is expanding rapidly. Climate Stability Bonds, as well as being versatile in the range of variables that they target, would reward people who achieve our goals, whoever they are and however they do so. Bondholders would do the work of identifying the causes and effects of climate change on a continuous basis. They would research, explore and implement those measures that will achieve the best return on our scarce resources. They will, very probably, implement a very broad range of measures on a diverse, adaptive basis: something that no government or supra-national body can do.
There are things that governments can do well. Indeed, there are things that only governments can do at all. These usually are areas in which causal relationships are clear and stable, and the benefits of an established approach are large and unchallenged. None of these conditions apply to climate change. It's time for a different approach.